I think the "when you bought them" might be the issue. I chunked two last year in a span of two weeks...same spot as you. Merc warranteed BOTH. They told me and Pier 57 that they had a bad run of props and it is weird how mine both went on the same spot. I bought my current ones from Lake Cumberland and they have been fine. I thought my drive was screwed but they looked in it and just chalked it to the bad run of props.